66 



to examine more closely the structural details. This species has also been 

 recorded by Norman from some localities on our western coast. 



Distribution. British Isles (Brady). 



Fossil - - Calabria (Seguenza). 



Gen. 7. Bairdia, M'Coy, 1844. 



Syn' Nesidea, Costa. 



Generic Characters. Shell short and tumid, more or less pronouncedly 

 rhomboid in shape, with the edges of the valves in most cases denticulate at 

 one or both extremities; surface in fresh specimens more or less densely clothed 

 with coarse recurved hairs. Both pairs of antennae considerably more slender 

 than in the preceding genus, the anterior ones carrying on the end a dense 

 fascicle of exceedingly long and slender setae; penultimate joint of the posterior 

 ones remarkably long and narrow. Mandibles and maxillae of essentially same 

 structure as in Bythocypris. Legs however still more slender, with the pen- 

 ultimate joint very long and narrow. Vibratory plate attached to the 1st pair 

 of legs (maxillipeds) rather larger than in that genus. Caudal rami with several 

 additional setae on the dorsal edge, apical claws very unequal in size, the proximal 

 one being much the longer and almost setiform. None of the legs in male 

 transformed; copulative appendages short and compact. 



Remarks. This genus was established as early as the year 1844 by M'Coy, 

 to comprise a number of fossil Ostracoda from the carboniferous limestone of 

 Ireland. Some of the forms included by him in that genus are however apparently 

 not congeneric, and for this raison most recent authors have found it advisable 

 to substitute the name Bairdia with that of Nesidea, proposed by Costa fo' 

 a species unquestionably belonging to the present genus. As however the forme: 

 name is the elder one, it ought certainly to be retained, though the genus 

 must be taken in a more restricted sense than done by M'Coy. 



A single species only, referable to the present genus, is represented 

 the Fauna of Norway. 



